Skip to content

Research at St Andrews

Can fear conditioning repel California sea lions from fishing activities?

Research output: Contribution to journalArticlepeer-review


Open Access permissions



Marine mammal interactions with fisheries create conflicts that can threaten human safety, economic interests and marine mammal survival. A deterrent that capitalizes on learning mechanisms, like fear conditioning, may enhance success while simultaneously balancing welfare concerns and reduce noise pollution. During fear conditioning, individuals learn the cues that precede the dangerous stimuli, and respond by avoiding the painful situations. We tested the efficacy of fear conditioning using acoustic stimuli for reducing California sea lion Zalophus californianus interactions from two fishing contexts in California, USA; bait barges and recreational fishing vessels. We performed conditioning trials on 24 individual sea lions interacting with bait barges. We tested for acquisition of conditioned fear by pairing a neutral tone with a startle stimulus. Avoidance was strongest in response to the startle stimulus alone, but low when paired with a neutral tone. From actively fishing vessels, we tested for fear conditioning by exposing sea lions to a neutral tone followed by a startle pulse, a startle pulse alone or a no sound control. We conducted playbacks from 146 (including 48 no sound control) stops over two summer fishing seasons (2013, 2014). The startle stimulus decreased surfacing frequency, reduced bait foraging and increased surfacing distance from the vessel while the conditioned stimulus only caused a mild reduction in surfacing frequency with no other behavioral change. Exposing animals to a pair of a conditioned stimulus with a startle pulse did not achieve the intended management outcome. Rather, it generated evidence (in two study contexts) of immediate learning that led to the reduction of the unconditioned response. Taken together, our results suggest that for fear conditioning to be applied as a non-lethal deterrent, careful consideration has to be given to individual behavior, the unconditioned/conditioned responses and the overall management goals.


Original languageEnglish
Pages (from-to)425-432
Number of pages8
JournalAnimal Conservation
Issue number5
Early online date30 Jan 2017
Publication statusPublished - Oct 2017

    Research areas

  • Conservation behavior, Marine mammal fisheries conflict, Fear conditioning, Non-lethal deterrents, Sea lions, Acoustic stimuli, Startle effect, Human-wildlife conflict

Discover related content
Find related publications, people, projects and more using interactive charts.

View graph of relations

Related by author

  1. The startle reflex in echolocating odontocetes: basic physiology and practical implications

    Götz, T., Pacini, A. F., Nachtigall, P. & Janik, V. M., 12 Mar 2020, In: Journal of Experimental Biology. 223, 12 p., jeb208470.

    Research output: Contribution to journalArticlepeer-review

  2. Effects of impulsive noise on marine mammals: investigating range-dependent risk

    Hastie, G., Merchant, N., Goetz, T., Russell, D. J. F., Thompson, P. & Janik, V. M., Jul 2019, In: Ecological Applications. 29, 5, 10 p., e01906.

    Research output: Contribution to journalArticlepeer-review

  3. The startle reflex in acoustic deterrence: an approach with universal applicability?

    Goetz, T. & Janik, V. M., 20 Jun 2016, In: Animal Conservation. 19, p. 225-226

    Research output: Contribution to journalArticlepeer-review

  4. Potential uses of anthropogenic noise as a source of information in animal sensory and communication systems

    Stansbury, A., Deecke, V., Gotz, T. & Janik, V. M., 1 Jan 2016, The Effects of Noise on Aquatic Life II. Popper, A. N. & Hawkins, A. (eds.). Springer, p. 1105-1111 (Advances in Experimental Medicine and Biology; vol. 875).

    Research output: Chapter in Book/Report/Conference proceedingConference contribution

Related by journal

  1. Animal Conservation (Journal)

    Monica Arso Civil (Reviewer)

    Mar 2017

    Activity: Publication peer-review and editorial work typesPeer review of manuscripts

Related by journal

  1. Fishing for the facts: river dolphin bycatch in a small-scale freshwater fishery in Bangladesh

    Dewhurst-Richman, N. I., Jones, J. P. G., Northridge, S., Ahmed, B., Brook, S., Freeman, R., Jepson, P., Mahood, S. P. & Turvey, S. T., 1 Aug 2019, In: Animal Conservation. Early View

    Research output: Contribution to journalArticlepeer-review

  2. Landscape-scale effects of single- and multiple small wind turbines on bat activity

    Minderman, J., Gillis, M., Daly, H. & Park, K., Oct 2017, In: Animal Conservation. 20, 5, p. 455-462

    Research output: Contribution to journalArticlepeer-review

  3. Rebuilding beluga stocks in West Greenland

    Heide-Jørgensen, M. P., Hansen, R. G., Fossette, S., Nielsen, N. H., Borchers, D. L., Stern, H. & Witting, L., Jun 2017, In: Animal Conservation. 20, 3, p. 282-293 11 p.

    Research output: Contribution to journalArticlepeer-review

ID: 246363318